a term used for a somewhat excited penis that is between the two stages of limp and boner, most guys will work their penis up to the jelly-wood stage before they whip it out to impress innocent bystanders

"Dude, What the fuck? What's your hand doin' in your pants?"
"Chill out man, I'm just tryin' to get a jelly-wood so I can flop my dick out."